Thread: Do You know the answer?

06012005, 07:20 PM #1
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 Apr 2005
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 63
Do You know the answer?
Here is one for you that I have no idea how they got the answer. Would be interested to find out though.
An involved second floor measures 125 ft. wide by 175 ft. long with an approximate ceiling height of 10 ft. What is the approximate gallonage needed for the fire flow?
a. 1500
b. 2000
c. 2200
d. 2500
Does anyone know how to answer this? I can't find an explanation or formula anywhere.
Thanks,
Scottsfire

06012005, 10:04 PM #2
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Hmmm...I don't know....the old length X width divided by 3 produces 7291.66, which isn't even close to any of the choices listed. Is this assuming 100% involvement?
Chief Dwayne LeBlanc
Paincourtville Volunteer Fire Department
Paincourtville, LA
"I have a dream. It's not a big dream, it's just a little dream. My dream — and I hope you don't find this too crazy — is that I would like the people of this community to feel that if, God forbid, there were a fire, calling the fire department would actually be a wise thing to do. You can't have people, if their houses are burning down, saying, 'Whatever you do, don't call the fire department!' That would be bad."
— C.D. Bales, "Roxanne"

06012005, 11:41 PM #3
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 Oct 2002
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the answer is c.2200. I got got 2188 with the Iowa State University formula (cubic feet involved/100=gpm required

06022005, 12:31 PM #4
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 Apr 2005
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Saylesville..........that is the correct answer according to the answer key but didn't know how the arrived at that answer. I'm assuming that this formula is taught in Delmars Pump book but I searched high and low in IFSTA and couldn't find anything!
Why is it called the Iowa State Formula.......did they think of it first?
Hey....thanks man I appreciate it.
Scottsfire
PS. Dmleblanc.....I kinda familiar with the formula you are using but isn't it "length x width x height= A then A is divided by 3" or am I wrong in adding the height in there?

06022005, 02:09 PM #5
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I don't want to jump in on Dmleblanc, but I believe he is talking about the NFA formula  L x W x # of floors divided by 3.

06022005, 04:41 PM #6
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 Apr 2005
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Spencer.......so needless to say this would be the calc for multistory buildings? If so, what is used on regular single story occupancies? I know there are a few out there but just wondering which would be most accurate........whats IFSAC going to want or use on their test?
Thanks,
Scottsfire

06022005, 07:22 PM #7
I was thinking of the DmLeblanc formula...........
IACOJ both divisions and PROUD OF IT !
Pardon me sir.. .....but I believe we are all over here !
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RAY WAS HERE 08/28/05
LETHA' FOREVA' ! 010607
I'm sorry, I haven't been paying much attention for the last 3 hours.....what were we discussing?
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http://www.firehouse.com/forums/show...60#post1137060post 115

06032005, 02:48 PM #8
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 Feb 2005
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 West Point, VA
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Scott,
You can use the same formula for single story dwellings. If the building is single story and 40 x 20 the forumula would read:
40 x 20 x 1
____________
3
So for single stories, you just use 40 x 20 divided by 3, or for two stories, it would be:
40 x 20 x 2
___________
3

06042005, 08:08 PM #9
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 Apr 2005
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Spencer,
I see........now it makes since.
Thanks for the info......
There is so much knowledge in these forums.
Scottsfire

06102005, 09:04 AM #10
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 Sep 2004
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 28
i know of about 6 different way to calculate fire flows each one will give a different gpm flow. Our department uses primarily the NFA quick calc method (LxWx# of floors/3) which was designed for the officer of the first engine on scene to find the fire flow with little math. This way is clearly not the way that the question wants you to do it.i will have to look throught my old school books to relearn how to do the other 5 methods.

06102005, 10:17 AM #11
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 May 1999
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 Berks County, PA
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Follow me on this one:
We can convert (Cubic Feet Involved / 100 gpm) into a "number of floors" version as follows:
CFI = L x W x H of involved area.
Assuming H = 10 ft. (residential), then we can reduce
(L x W x 10) / 100 to (L x W x 1) / 10
and this will work as (L x W x #floors) / 10, giving the same answer as CFI / 100 for residential structures.
If we assume 12 ft. floors for commercial structures, it becomes:
(L x W x #floors x 1.2) / 10, or approximately
(L x W x #floors) / 8 for commercial structures, such as office buildings.
To get (L x W x #floors) / 3, to be equivalent to CFI / 100, we need the floors to be approximately 33 ft. in height. This may be true for an industrial, warehouse or large retail building.
So, assuming CFI / 100 is the exact calculation, shouldn't the "quickie" calculations be:
(L x W x #floors) / 10 for residential
(L x W x #floors) / 8 for commercial
(L x W x #floors) / 3 for industrial/large commercial?
Any insights?Last edited by bobsnyder; 06102005 at 10:21 AM.

06102005, 09:20 PM #12
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 Sep 2004
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 28
Bob,
I think i follow what you are saying. It makes sense to me, i think the way you are talking about is a more precise way. It takes into account that different structure types have different fuel loadings (like the Branigain(sp?) fire flow method) However and the is just my thought on the matter in order to keep it to a mental math level go with divided by three. To me this would be an easier calculation for the first officer onscene to do in his head when he is entering the fire block. The officer can see the building estimate the L and W, count the floors and, do the math in his head. this would enable the officer to get a some what close fire flow in his head to better understanding what fire flow he needs for the building. By dividing by three it limits the difference between the estimated L and W and the real L and W. Also it gives you the highest GPM flow to take into acount the estimated L and W. Any thoughts

06142005, 08:31 PM #13
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 Feb 2004
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 106
It is the Iowa State formula, though I cannot tell you why it is called that.
The formula is LENGTH X WIDTH X HEIGHT divided by 100. That comes to about 2187, or 2200 GPM as the answer.
Just what Saylesville said. I had to restate it in terms I could understand to make myself feel better! Sorry.

06142005, 11:31 PM #14
Okay, I have my 'SpartanGuy' formula. It goes like this.
Judge what you have by your preexisting knowledge of the building's fire load and bank on your experience as a line officer/pump operator/firefighter and pull the appropriate sized line. Take it to the seat of the fire and apply water to that location.
If it doesn't make much progress, call in another line of equal or greater size.
Just think and you don't have to play around with any math!"Captain 1 to control, retone this as a structure and notify the fire chief...."
Safety is no accident.

06172005, 09:19 PM #15
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 Jan 2005
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 1
just for further info....if you would like it... there is a link in the Training section of firehouse.com titled, "How good is your scene sizeup?", which will go into detail about calculating gallonage. It is under III. Fire Conditions > Water requirements.
hope this helps.

06172005, 09:37 PM #16
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 Apr 2005
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 63
Jr.
Thanks bro I'll check it out!
Scottsfire

06172005, 10:47 PM #17
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Originally posted by SpartanGuy
If it doesn't make much progress, call in another line of equal or greater size.
Just think and you don't have to play around with any math!
Sometimes math is good.
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